hey guys, my 37 currently has an old mercury rear diff and I am planning to swap for a 8". anyone know what wodth or critical dimensions I need. or better yet what year card would work best? I have new TCI rear leaf set up and need to add a new diff. thanks
I may be wrong but I believe most 8" rears are all the same dimension. The only difference I know is 4 lug and 5 lug. You'll likely want the latter.
It really depends on your wheel offset and backspacing. Do you already have the wheels you are going to use? Use your wheels/tires mocked up in the fender to get a measurement ( or measure your current rearend if it is right), and the start hitting every swap meet you can get to. All 8" rears are not the same. I have thee of them right now. The maverick is 56" The '65 mustang is 57 1/4" The '67 fairlane is about 59" I'm sure your going to need something in this range, depending on your wheels. Probably mustang or maverick.
I have just finished up my '40 to make it driveable. I did a lot of research to find out what 8" would be ideal. What I came up with was '65-'66 mustang was best fit. What I ended up using was '68 Mustang which is I think the same width as a stock '40 rearend. I think the perfect rear, if you want wider rims, would be '64 Fairlane, but harder to find. I used Ch***is Engineering parallel leaf kit and the '68 rear bolted right up without moving spring pads. The trade off is that my rims are LTD stock steelies 6.5" wide, 235/70/R15 tires. Check out my thread "Fresh off the trailer" to see how they look.
I used a 8" Maverick Grabber in my 40 pickup so I could run wider rims and a 8" Granada in my 40 coupe at about 1” or so wider than the Maverick.
I have a 1978 Mustang II rear end in my 1929 A Roadster, a Maverick rear end in my 1932 Ford And my son put a Ford Granada/Mercury Monarch rear end in his 1940 Ford Pickup. All have the 8 inch center section. They all work just fine as Henry made them. Posted using the Full Custom H.A.M.B. App!
A 5-lug, 8" from a '74-'77 Merc Comet worked just fine in a '40 Ford 2-dr. we built recently. All the Maverick/Comet rearends with 5 lugs are referred to as V-8 pieces. If you are intending to go posi-trac, you might want to just go with a 9" Ford. My posi unit for my 8" was $600 dollars. Just wanted to inform you. Next rod will be a 9". Good luck.
I have a Granada 8-inch in my 37. Bolts onto Ch***is Engineering parallel leaf kit. I'm running the factory 7-inch rims used on police cars and some high performance cars. Would occasionally get the tire to touch sheetmetal on a turn if I had several people in the car. Added those thin spacers (maybe 1/8-inch) and haven't had another touch in over 20 years.
Used a Maverick 8" in my since sold 37 Tudor. With a mild 355" SBC it was fine and there are plenty of gear options. I used 7" wheels but don't recall the backspacing.
TCI use an axle width of 56.5 inches in all their 35-40 Ford Ch***is. Maverick 8" is that exact width and is the way to go.
looks like I will be on the hunt for maverick rear. seems to be the one that fits best.thanks for the input
Later model 8.8 will be easier to find and may be less money. wms to wms: Ford Explorer 8.8 1992-2009 59½” Ford Ranger 8.8 1990-1992 56½” 1993-2009 58½” .
Found this list here- http://www.mustangsandmore.com/ubb/FordRearDimensions.html Ford Rear Dimensions by Dave_C and the Fordnatics mailing list. Here is a list of rear ends that I picked up some time ago on the Fordnatics mailing list. These measurements are from flange to flange. Subtract 5" for bare housing length. 65-66 Mustang 57.25 inches 67-70 Mustang 59.25 inches 71-73 Mustang 61.25 inches 77-81 Versailles 58.50 inches 74 Maverick 8" 56.50 inches 75 Mustang II 8" 57.00 inches 67-73 Mustang, Torino, Ranchero, Fairlane 9" 59.25 inches to 61.25 inches 57-59 Ranchero and station wagon rears, 57.25 inches 66-77 Bronco 9", 58 inches 77-81 Granada/Versailles, 58 inches 67-71 Comet, Cougar, Mustang, Fairlane, 59.25 inches 71-73 Mustang, 61.25 inches 64 Falcon 58 inches 67 Cougar 60 inches 67 Fairlane 63.50 inches (coil springs) 72 Ford Van 3/4 ton 68 inches 73-86 65.25 inches 57-59 Ranchero and station wagon 57.25 iches (narrowest 9" housing) 66-77 Bronco 58 inches but has 5-on-5 1/2 inch diameter bolt circle 67-73 Torinos, Rancheros, Fairlanes 59.25 inches or 61.25 inches 67-71 Comets, Cougars, Fairlanes 59.25 inches Where to find the 9" rear axle 67-73 medium and big block Mustangs and Cougars 66-71 Fairlanes, Torinos, Montegos, Comets, and other Ford intermediates with big blocks 57-59 V8 Fords and Mercurys 77-81 Lincoln Versailles & Trucks Type of 9" axle housings 67-73 Mustang/Cougar - light duty, thinnest housing material, small axle bearings, 28 and 31 splines 57-68 p***enger car and 1/2 ton truck - medium duty, stronger than Mustang type, 28 and 31 splines Ranchero/Torino - heavy duty thick wall housing, 3.25 inch diameter axle tubes with flat tops 69-77 Galaxies (coils), Lincolns (coils), and late pickups (leaf)- 3.25 inch diameter all the way to the backing plate, coil housings have upper control arm mount How to recognize 9" housing centers 57 - no dimples, flat center band up the center of the rear cover, bottom drain plug 58-59 - two dimples on back of housing, flat center band, some had drain holes 60-67 - two dimples, flat center band, oil level hole in back cover 63-77 Lincoln, LTD, Thunderbirds had 9.375 inch centers, housings were cut away at the gasket surface for ring gear clearance, one curved rib at the front top portion of differential. Strong, but no gears. Types of 9" Axles 28 spline axles cannot be shortened and resplined (they're tapered) Some can: 69-73 Mustang and Cougars have a straight 28 spline axle. 72 and earlier 31 spline axles have the ability to be shortened 73 and later 9" (big cars) have a 5-on-5 bolt circle and the axles cannot be shortened 67-73 Mustang axles identified by wheel flange: oval hole - 28 splines two large holes and counter sunk center - 31 splines
If anyone wants to know, the stock 40 Ford car rear is 59 1/2 inches wheel mounting surface to wheel mounting surface.
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